Hi, For the reason you observed, I normally set upmap_max_deviation = 1 on all clusters I get my hands on. Cheers, Dan -- Dan van der Ster CTO Clyso GmbH p: +49 89 215252722 | a: Vancouver, Canada w: https://clyso.com | e: dan.vanderster@clyso.com We are hiring: https://www.clyso.com/jobs/ Try our Ceph Analyzer! https://analyzer.clyso.com/ On Mon, Nov 27, 2023 at 10:30 AM <bryansoong21@gmail.com> wrote:

Hello,

We are running a pacific 16.2.10 cluster and enabled the balancer module, here is the configuration:

[root@ceph-1 ~]# ceph balancer status { "active": true, "last_optimize_duration": "0:00:00.052548", "last_optimize_started": "Fri Nov 17 17:09:57 2023", "mode": "upmap", "optimize_result": "Unable to find further optimization, or pool(s) pg_num is decreasing, or distribution is already perfect", "plans": [] } [root@ceph-1 ~]# ceph balancer eval current cluster score 0.017742 (lower is better)

Here is the balancer configuration of upmap_max_deviation: # ceph config get mgr mgr/balancer/upmap_max_deviation 5

We have two different types of OSDS, one is 7681G and another is 3840G. When I checked our PG distribution on each type of OSD, I found the PG distribution is not evenly, for the 7681G OSDs, the OSD distribution varies from 136 to 158; while for the 3840G OSDs, it varies from 60 to 83, seems the upmap_max_deviation is almost +/- 10. So I just wondering if this is expected or do I need to change the upmap_max_deviation to a smaller value.

Thanks for answering my question. _______________________________________________ ceph-users mailing list -- ceph-users@ceph.io To unsubscribe send an email to ceph-users-leave@ceph.io